Supercharger



June 5, 1951 BQLLAY 2,555,312

SUPERCHARGER Filed Jan. 24, 1947 FIGV V FIG 111 f m v V V f ,f A FIGDZ W Vu v I y may LIAM. BOL'LAY very poor under throttled conditions.

l atentecl June 195l UNITED STATES ATENT OFFICE 2,555,312 SUPEBCHARGER William Bollay, Palisades, Calif.

Application January24, 1947, Serial No. 724,222

3 Claims.

(Granted under the act of March 3, .1883, as amended April 30, 1928; 37.0 0. G. 757) This invention relates to improvements in superchargers and 'is particularly directed to a device for evening out non-uniformity in airfiow at the inlet of a supercharger.

In conventional type superchargers having an inlet elbow and a main-stage rotary impeller rotor, the distribution .of velocity behind the carburetor at the outletof the air inlet elbow is This results in a poor distribution of fueleair mixture in the enginecylinders and consequently in excessive cylinder head temperatures.

Anumber of devices have been tried to recti- 'fy this situation, each device attempting to even out the flow of theair-as it'travels along thestationary shrouds of the inlet elbow. However, it has been found that the air distribution is extremely non-uniform. Stationary guide vanes have been used'with very little-success in rectifying this problem. These devices are objectionable because of the very high pressure drop associated with them, and the danger of icing of stationary guide vanes.

An object of this invention is to provide a device which transfers energy in the inlet elbow from regions of high velocity to regions of low velocity, thereby giving an improved air distribution to the engine and overcoming the difiiculties specifically outlined above.

Other objects and advantages of this invention will become apparent as the discussion proceeds and is considered in connection with the accompanying claims and drawings, wherein like characters of reference designate like parts in the several views and wherein:

Fig. I is a perspective view of the auxiliary rotor embodied in this invention;

Fig. II is a cross-sectional view of the rotor embodied in this invention in position in a supercharger; and

Figs. III, IV, and V are diagrammatic illustrations showing the airfoil principle of operation of this invention.

Referring now to the drawings, wherein for the purpose of illustration is shown a preferred embodiment of this invention, the numeral 5 designates a drive shaft carrying a conventional mainstage impeller rotor 6. The numeral 1 designates a stationary housing or shroud having an air inlet elbow 8. Fuel is metered by a carburetor or other conventional apparatus (not shown) and is injected into the air stream in any conventional manner, either in the elbow 8 or in the rotor 6. The air or air-fuel mixture is compressed by the impeller and is exhausted under increased pres- 2 sure from an outlet to a manifoldor the like of anengine (not shown).

Just ahead of the impeller 6 is .rotatably mounted an auxiliary rotor stage or impeller 10. The auxiliary rotor is independently carried by roller, ball or sleeve bearings I I, mounted upon the shaft 5. The auxiliary rotor 19 is provided with vanes'or airfoils .12, arranged in lattices of solidity ranging between about 0.5 and 2.0, and

adapted to rotate independently from the shaft t. Rotation of the said auxiliary rotor 1,0 .is caused by the movement of the .air .or fuel-air mixture in the elbow B.

It is to be here noted that *whilethe auxiliary impeller '13 is located just ahead of or-upstream from the face-of the impeller .6, it may bierlocated at any conventional place in the air inlet elbow; 8

between thecarburetor and the main=stage impeller S. The pitch angle .of the vanes or airfoils i2 will of course vary with the specific characteristics of each impeller, but should preferably be fixed somewhere between 30 and degrees with respect to the plan of rotation of the rotor depending upon the effectiveness desired. The preferred vane or airfoil shape is symmetrical so that the section is equally adapted for driving as well as for absorbing power.

The principle of operation in transferring energy from high-velocity regions to low velocity regions is illustrated in Figs. III, IV, and V. Let Va be the axial and Vu be the rotational component of the relative velocity with respect to the rotor. If the axial component of velocity Va is high (such as in Fig. III) then the airfoils experience a driving force tending to accelerate the rotor, i. e., this section of the rotor acts as a windmill or turbine. If the axial component of velocity Va is low (such as in Fig. V), then the airfoils tend to speed up the airflow, i. e., this section of the rotor acts as a compressor or fan. If the axial component of velocity is along the direction of the axis of zero-lift of the airfoils (such as in Fig. IV), then the airfoils neither drive nor are driven. Thus it is seen that if there is a non-uniform inflow velocity into the rotor, the regions of high axial velocity (high energy) lose energy because the rotor locally acts as a turbine. Similarly, the regions of low axial velocity (low energy) gain energy because the rotor locally acts as a compressor.

In operation, air is introduced in the conventional manner, into the inlet elbow 8, it then travels down the elbow until it reaches the auxiliary impeller rotor it. Due to the configuration of the vanes or airfoils l2, the said impeller will be forced to rotate as the air passes through the vanes. The distribution of the velocity of the airflow is caused to be evened out by the rotor I and enters the main-stage impeller 6 in a symmetrical flow pattern, where it is then uniformly compressed and discharged to the cylinders by way of the exhaust 9. The direction of rotation of the auxiliary rotor 10 can be either with or against the direction of rotation of the main-stage supercharger impeller. If it turns in the same direction as the mainstage impeller, the efliciency of introducing the air will be improved, but the pressure rise will be somewhat reduced. If it turns in the opposite direction as the main-stage impeller, the emciency of the supercharger will suffer slightly but the pressure rise will be slightly higher, thus either the same or opposite rotation will fulfill the spirit embodied in this invention.

It is to be understood that the form of this invention, herewith shown and described, is to be taken as a preferred example of the same,

and that various changes in the shape, size and arrangement of parts may be resorted to, without departing from the spirit of this invention, or the scope of the subjoined claims.

The invention described herein may be manufactured and used by or for the Government of the United States of America for governmental purposes without the payment of an royalties thereon or therefor.

What is claimed is:

1. A supercharger comprising a casing with an inlet and an outlet for throttled air, a shaft J'ournalled in said casing, a main vane impeller fixed to the shaft for rotation therewith, an axial flow type auxiliary vane impeller mounted for free rotation relative to said shaft, said 4 axial flow auxiliary vane impeller being positioned in the path of the incoming air and being the first impeller between the air inlet and the main vane impeller, and said auxiliary vane impeller having vanes arranged in lattices and being rotatably responsive to the velocity of the throttled incoming air so as to increase and decrease its rate of rotation with the increase and decrease of the velocity of incoming air in order to increase the uniformity of velocity of the air reaching the main vane impellezz,

2. The combination of claim 1 further defined in that the vanes of the auxiliary vane propeller are formed to cause said auxiliary impeller to rotate in a direction opposite to the direction of rotation of the said main vane impeller.

3. The combination of claim 1 further defined in that the vaned axial flow auxiliary impeller is mounted on antifriction bearings for free turning and that the vanes are arranged in lattices of solidity ranging approximately from 0.5 to 2.0 and have a pitch angle of between and degrees with respect to the plane of rotation of the auxiliary vane impeller.

WILLIAM BQLLAY.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 921,118 Kasley May 11, 1909 1,143,255 Dornes June 15, 1915 2,321,276 De Bolt June 8, 1943 2,349,731 Hornschuch May 23, 1944 2,400,240 Lincoln May 14, 1946 2,450,745 Baumann Oct. 5, 1948 

